毛细管电泳脉冲安培检测药物制剂中的氨基酸

Determination of Amino Acids in Pharmaceutical Preparation by Capillary Electrophoresis with Pulsed Amperometric Detection

基于毛细管电泳三脉冲安培检测技术,同时测定了氨基酸注射液中具有电活性的色氨酸和酪氨酸的含量。研究了三脉冲电位及时间、电解液的浓度、酸度、电泳电压及进样时间对电泳分离和检测的影响,得到了最优测定条件。以铂微盘电极为工作电极,Ag/AgCl为参比电极,三脉冲电位为:E1-900mV,t1100ms;E2700mV,t2100ms;E3950mV,t3100ms,在15mmol/L的磷酸盐(pH=11)缓冲溶液中,上述两组分在10min内完全分离。测定色氨酸和酪氨酸的线性范围分别为1×10-3～5×10-7mol/L和1×10-3～8×10-7mol/L,检出限分别为0.25μmol/L和0.17μmol/L(S/N=3);平行进样的峰电流相对标准偏差(RSD)分别为2.9%和3.3%(n=7)。

Based on capillary electrophorersis with pulse amperometric detection technique, a method was developed for the simultaneous determination of tryptophane and tyrosine in medically-used 18-Amino Acid Injection. The effects of potentials and time periods for pulse amperometric detection, concentration and pH value of electrolyte, separation voltage and injection time on the analytical characterization were investigated. A Pt disk-shaped electrode was used as the working electrode. The pulse sequence used for amino acid detection in this study was as follows,950 mV for 200 ms with 100 ms data collection,700 mV for 100 ms to activate the electrode, and -900 mV for 100 ms to condition the electrode. Tryptophane and tyrosine could be well separated within 10 min in a 15mmol/L phosphate buffer at (pH 11.) An excellent linear relationship existed between peak current and analyte concentration in the range of 1×10^(-3)～5×10^(-7)mol/L for tryptophane and 1×10^(-3) ～ 8×10^(-7) mol/L for tyrosine with the detection limits(S/N=3) of 0.25 μmol/L and 0.17 μmol/L for tryptophane and tyrosine, respectively. The precisions of the peak currents were obtained for 7 successive determinations of two amino acids studied both at 0.04 mmol/L with RSDs of 2.9% for tryptophane and 3.3% for tyrosine.